Light emitting diodes (LEDs) are used for a multitude of applications, including in particular signaling and, nowadays to an increasing extent, general illumination applications. Depending on the application and the type of LED used, various designs of driving circuits for LEDs exist. Due to the exponential dependence between operating current and voltage, similarly to other diodes, LEDs are typically driven with a constant current power-supply unit or driving circuit. Most simply, the driving circuit may consist of a series resistor to limit the maximum current delivered to the light emitting diode in case of a variation of the operating voltage. Certainly, due to the relatively high losses, such an arrangement may be particularly unsuitable for lighting applications, e.g. in combination with high-power LEDs. Besides the above mentioned simple driving circuit with a series resistor, other driving circuits exist in the art. However, such circuits typically are elaborate and thus costly. Additionally, the circuit design in most cases needs to be adapted to the type and number of LEDs used, providing limited scalability. Thus, in particular for the emerging use of LEDs in general illumination applications, such circuits may be unsuitable.
Therefore, it is an object of the present invention to provide an LED circuit arrangement enabling efficient operation of an LED light source, i.e. with reduced loss, and having a cost-optimized circuit design.